Ashless detergent additive for lubricating oils



2,764,551 ASHLESS DETERGENT ADDITIVE FOR LUBRICATING OILS Paul -V. Smith, Jr., Westfield, Samuel B.' 'Lippincott, Springfield, and Cliiford W. Muessig, Breton -Wods, N. J'., assignors to Esso Research-and Engineering Company, a corporation of Delaware No-Drawing. Application May 17, 1954, Serial No. 430,418 6' Claims. (Cl. 252-515) This invention relates to a new class of compounds which'are particularly suitable for use as detergent additives in lubricating oil compositions. More particularly-the-present invention relates to anew class of compounds of the complex ester type which are formed "by reacting a dibasic acid with a glycol and an amino alcohol. The invention also relates to lubricating oil compositions containing such new compoundszas detergent additives.

The art of metallic detergents for lubricating oil compositions adapted for use in internal combustion engines is well known to those versed in this field and has resulted in substantial improvements in lubricants. These detergents .are particularly useful in lubricating oil compositions which are employed in internal combustion engines used in the operations of automobiles, aircraft, and similar vehicles, including diesel engines, to improve their operation by preventing or retarding. corrosion, piston ring sticking, cylinder wear, and carbon and varnish formation. However, when metallic detergents are usedin lubricating compositions where oil'consumption'is high and engine conditionsare severe, such as in aircraft engines or where such concentrations of metallic detergents areused to maintain engine cleanlinessunder conditions where high deposit fuels of cracked or high sulfur nature are used such as inv automobile and diesel operation, the ash content from the metallic detergent accumulates in the combustion chamber and .is believed to cause pre-ignition, detonation, spark plug fouling, and valve burning.

Because these deficiencies of metallic detergents have been previously recognized, certain non-metallic .or ash.- less detergents have been developed. However the performances of the ashless detergents of the prior art have not been entirely successful in regard to detergency. More specifically, the prior art ashless detergents have been inadequate in keeping deposit-forming...materials suspended in the oil to thereby prevent coke, varnish,: and

United States Patent other deposits from forming on critical engine parts. The

present invention is designed toovercome this particular deficiency of the ashless detergentsof the prior. artz It is also an object of this-invention to provide a detergent additive which is superior to themetallic:detergentszof the prior art in regard to detergency as well as to ash content.

The new compounds of the present invention are of the complex ester type formed by reacting a dibasic acid with a-glycol and an aliphatic monohydric-alcohol as follows:

one)-[ ra 1rer rana e where b is an integer of value 1 to 5 and :atlleast one of the. two-aliphatic monohydric alcohols isia tertiary-"amino alcohol. More particularly the new compounds.- of the present invention have the following generalrformular ice where R and R1 are alkyl radicals .eachcontaining. .lxto 10 carbon atoms; R2 is a radical selectedv from .the group consisting of (1) alkyl radicals containingLto 20; carbon atoms derived from primary alcohols and (2) radicals of the formula /Rr (C 2) r-N a.

where b is an integer.of. value 2 to 4 and R4 and Raare alkyl radica'ls containing 1 to '10 carbon atoms; X is a member selected from the group consisting of oxygen atoms and sulfur atoms; a;is an integer of value 2 to 4; m is an integer of value 0 to 8; nuis. aninteger of -value..2 to. 1'0; y'i's an integer of value 0 to5'; and :Z isian integer of value l'to 5. "The molecular weightof. the entireester should be atleast 3"00and the various components of the ester should be selected so as to form an oil-soluble ester product. 7

The complex esters of this invention may be prepared by'general esterification'methods such as the method outlined in U. "S; Patent 2,575,195, wherein the esters are prepared by a stepwise procedure. It will be understood however that the complex esters of this invention may :also be prepared in a one-step procedure wherein the appropriate"molecular proportions of all of the various HQOC (CH2) mCOOH where m is an integeriof-value 0 to 8. dibasic acids are the following:

These organic Oxalic Pimelic Malonic Suberic Succinic wAzelaicv Glutaric Sebacic Adipic The glycolsempl'oyed' in preparing the esters'of the present invention have the general formula rvwhereq-Xrrepresenta anz'zoxygen or sulfur atom; nis an integer :of value 2111:0 10 and y. is an integer: of'-=v-al'ue .OxtovSf. .Exampl'esof these .glycolsaare the'fo-llowingz' Diethylene glycol 13 propylene glycol Triethylene glycol -l,,lpropylene glycol Tetraethylene glycol 1,4-butylene glycol Pentaethyleneglycol; 'li-3 butylene glycol Dipropylene glycol Hexamethylene' glycol -'I ripropyleneg1ycol Decamethylene glycol I hiodiglycol 'Neopentylg'lycol' Ethylene The monohydric alcoholsof' this .invention which acon.- tain a tertiary amino. gronp...have.the generalformula fiiworn) ton Rf where R and Ri-eaach represent'alkyl radicalscontainingjl to 10 carbon atoms and a is an integer of value 2 to 4. flask were maintained at about 111 C. and atmospheric These alcohols are typified by the following: pressure for a period of 11 hours during; whifh time 7.2

cc. of water were removed from the fias wit the watergiggggi fig fii fi entraining toluene. Thereafter the contents of the flask Dipropylaminoethanol 5 were sub ected :to a distillation step which was carried Dibutylaminoethanol out at 0.5 mm. of pressure and ata temperature of 180 di .(2 ethy1buty1)aminoethanol C. to remove all materials boiling below 450 C. at Di n hexylaminoethanol atmospheric pressure. The residue in the flask amounted Di ,(z ethylhexyl)aminosthanol to about 71 grams and represented the complex ester Di C8 oxoaminoethanol 10 made in accordance with the present invention. The com- Di cm oxoaminoethanol plex ester had the following approximate analysis:

Dimethylaminopropanol I Dimethylaminobutanol ConsItiTtuent. Weight percgn The non-amino or regular alcohols of this i n n Cj:::::::::::::::::::::::::.::::1:33:21: 6912 have :the general formula H 1L8 ROH Based on the proportions of reactants employed and where R is an alkyl radical derived from a primary althe above analysis, it is believed that the resultant prodcohol containing 1 to carbon atoms. Illustrative net is a mixture of complex esters and that this mixture examples of these non-amino alcohols which may be em- 20 includes compounds having the following formulae:

ployed in preparing the complex esters of the present invention are as follows:

Methyl Heptyl This complex ester product prepared above had a flash point of about 435 F., a pour point of less than 35 F., and had a kinematic viscosity of about 61.25 at 100 F. and a kinematic viscosity of about 8.55 at 210 F.

Ethyl Octyl In order to determine the suitability of the above com- PY Nonyl plex ester as a detergent additive in lubricating oil com- Butyl Decyl positions and also to determine its effectiveness in this Isobutyl Dodecyl regard as compared to the prior art detergent additives 3231 gzgz the following compositions were prepared:

1 h 1 u d d f Composition A A rou of non-amino a co os es ecia a a te or use iii cor inection with the present ir iventi h are the so- Thls partlcular @mposmon conslsteii of by Weight called alcohols Prapared by the reaction of carbon of the complex ester of the present invention prepared monoxide and hydrogen upon the olefins obtainable from by the aforedescnbed Procedure and i by 5 of petroleum products. Materials such as diis'obutylene and a h Q Solvent dell/axed F ,nhered,mmer9f1 olefins are suitable for this mimosa Also higher mo1ec lubricatmg Oli base stock having a viscosity of 1 18 centiular weight olefinic materials are sometimes employed. Stokes at 100 and 1134 cemlsmkes 210 The alcohols obtained in this manner normally have a Composition B branched chain structure.

Am i i of m l x esters of g zgs z g ggg 223 22; i z gg be of a commercially ava1lable ashless detergent add1t1ve pointed out. The preferred dibasic acids are adipic, the prior art and by h of the lubricating azaleic and sebacic; the preferred glycols are ethylene 011 base stock employed In Composition glycol and polyethylene glycols of the formula- Composition C HO (CH2CH2O dCHzCHzOH of the lubricating oil base stock employed in Compo- Whefe d an integer of Value 1 t0 the Preferfed mono sition A and 8% by Weight of an additive blend consisthydric amino alcohols are diethylaminoethanol and diing f 5% f dpisobutfl Phenol fid d 375% butylaminoethanol; and the preferred monohydric nonf calcium Petroleum ulf at amino alcohols are the C8 to C13 Oxo alcohols. These components are preferred because they are readily avail- Composition D able commercially and also because they produce an oil- Thi particular composition consisted of 92% by weight soluble ester product on account of their chain lengths. 65 of the lubricating oil base stock employed in Composi- As an example of the present invention, a complex tion A and 8% by weight of an additive blend consistester exhibiting unusually desirable detergent characterising of 62.5% of calcium di-isobutyl phenol sulfide and ties was prepared as follows: 50 grams of sebacic acid, 9 37.5% of calcium petroleum sulfonates. grams of ethylene glycol, 28 grams of C13 Oxo alcohol These four compositions and the lubricating oil base and 17 grams of diethylaminoethanol were added to 200 stock itself were then subjected to a Phorone-HzSOa. cc. of toluene in a 1 liter flask. The toluene was ernscreening test in accordance with the procedure set forth ployed as an azeotroping or water-entraining medium for in Serial Number 327,516 by Charles S. Lynch and Elmer removing the water formed in the esterification reac- B. Cyphers, now Patent No. 2,732,285, issued January tion. The flask was equipped with astirrer, thermometer, 24, 1956. This particular test is based on the theory condenser and water take-off trap. The contents of the that the blow-by of fuel combustion products into an This particular composition consisted of 4% by weight This particular composition consisted of 92% by weight a Lu k.

. (Composition B) The Phorone test is preferred over full-scale engine a-nd road tests because it is-economicalsince it requiresconsiderably less time and equipment thando the full-scale tests.

Intesting :the above compositions-100 grams of each composition was placed in a beaker together with: See. J

of phorone. From 1 to -9.ml. of 10% H2504 were added to the compositions and the contents of each beaker were stirred for '40 'minutes at a temperature of 275 Thereafter, theliquid content of'each beaker was removed by pouring and the beakerswere rinsed with heptane and wiped with a dry cheesecloth. The weightof hard beaker: deposits (sludge) remaining-wasthen-determined after a second rinse and drying step.

The results of the Phorone-H2SO4--tests on'the four compositions and the lubricating oil basestock itself were 525 as follows:

10% Sludge Composition ZHQSO; :(mg.)

Base Stock 1 10 A 9 0 5 6 8 105 8. 5 I 8 m8 v.12 {j These results show that the complex-ester of: the spresent invention is ideally suited for utilization as :aadetergent additive in lubricating compositions. 5:Not,only:zis;it -an ashless additive but it also demonstrates :excellent dC-i tergent properties. It will be noted-thateallwOfythezcompositions which contain detergentadditives (Compositions'A, B, C and D) represented .animprovemcntin regard to detergency as compared to the lubricatiuggoil base stock itself. The compositions containing. metalli ,45

detergents (Compositions C and D):.showedr:better detergency properties thandid the composition, containing the commercially available ashless detergent additive However, it. will of:.course:?;be noted that Compositions CY and .D- contained-twice the additive ,50

concentration of Composition B (8% vs. 4%). ,Composition Acontaining'the complex ester of the presentinvention was subjectedtothe mostsevere conditions in these experiments with 9 ml. of 10% 'H2SO4 being "employed. Yet even at-this severity Composition Ashowed no measurable amount of sludge. It will be noted that at lower testing seventies the ashless detergents and metallic detergents of the prior art showed substantially more sludge formation than the composition made in accordance with the present invention. even though the metallic detergents were employed in concentrations which were twice as much as that in the composition containing the additive of the present invention (8% vs. 4%).

When additives of the present invention are employed in lubricating oils, they are usually added in proportions of about 0.001 to about 10.0% by weight and preferably 1.0 to 6.0% by weight. The proportions giving the best results will vary somewhat according to the nature of the additive and the specific purpose which the lubricant is 70 in such form. In preparing a lubricating oil composition 75 This was so ayza naat iforuiuseztas a :crankc'ase: :lubricant .:the-. additive concentrate ::is :merely 'fb161'ld6d!Witl1.Tfl1e :base: oil widthewrequired 'amount.

illhezupnoducts of thevpresentfinvention may beem- ;ployed .not only-sin ordinary-hydrocarbon lubricating oils butalso. in theiheavy dutyttype of lubricating oils which :have beenocompounded with :such detergenttype addi- -tives-aswmetal' soaps, metalapetroleum sulfonates, metal phenatesymetal alcoholates, metal'alkyl phenol sulfides, metali-uorganophosphates,thiophosphates, phosphites and thiophosphites, metal salicylates, metal xanthatesand -t=hioxanthates,-- metal' 'thiocarbamates,- amines and amine derivatives, reaction products of metal phenates and :sulfur, reaction products -ofmetal-phenates and-phos- :phorus sulfides, metal phenol sulfonates and the like. Thus the-additives'of the present invention may be used in"- lubricating oils' containing such other addition-agents as barium tert.-octylphenolsulfide, calcium tert.-amylphenol sulfide, nickel oleate'; barium octadecylate, calcium phenyl stearate, zinc diisopropyl salicylate, aluminum naphthenate, calcium cetyl'phosphate, bariumdi-tertamylphenol sulfide, calcium petroleum sulfonate, zinc =methylcyclohexyl'thiophosphate, calcium dichlorostearate, "etc. -fOther-types Of-additivessuch-as phenols and phenol sulfides, may beemployed.

The lubricating oilbasestocksnsed in thecompositions "ofrthis inventionmay be straight mineral lubricating oils gor"disti'llatesderived fronrparafiinic, naphthenic, asphaltic, "or rnixedbase*cru'des,-or,;if desired, various blended oils "may-be employed as 'well as residuals, particularlythose 'from'which asphaltic, constituents have been carefully re moved. The oils maybe refined by conventional methods 'using-acidyalkali-and/or 'clay 'or'other agents such as aluminum chloride, or ,theymay beyextracted oils produced; for*examp1e,"bysolvent extraction :with solvents of 'thelrtype of'phen'ol, sulfur dioxide, furfural, dichlorodietjlryl ether, 'nitrobenzene, crotonaldehyde, etc. Hydro- ;genatedioils white oils,;or shale oil may be employed as "wellassynthetic oils, such as lubricating grade simple and complex-esters-of dibasic acids, carbonates and organic phenylates, polyethers, simple and complex formals, polyethyleneglycols, etc., as well as those prepared, for example; by the polymerization-ofolefins or by the reaction of oxides of carbon witli'hydrogen orby the hydrogenation "ofcoali'or its-products. Also, for special applications, "animal,'-vegetable or'fish'oils or their'hydrogenated or v'oltolized products may be employed in. admixture with mineral oils.

For the best results 'thebase'stock chosen should normally be that oilwhich withoutthe new additive present gives theoptimum performance in the service contemplated. "Howevensince one advantage of the additives is "that their use also makes feasible'theemployment of less satisfactorymineral oilsorother oils, no strict rule can belaid down-for the choice, of-the base stock. Certain *essentia-lsmust of coursebe observed. The oil must possess the viscosity 'and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the additive, although in some cases auxiliary solvent agents maybemsed. The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to 150 seconds Saybolt viscosity at 210 F. For the lubricating of certain low and medium speed Diesel engines the general practice has often been to use a lubricating oil base stock prepared from naphthenic or aromatic crudes and having a Saybolt viscosity at 210 F. of 45 to 90 seconds and a viscosity index of 0 to 50. However, in certain types of Diesel engine and other gasoline engine service, oils of higher viscosity index are often preferred, for example, up to to 100, or even higher, viscosity index.

In addition to the material to be added according to the present invention, other agents may also be used such as dyes, pour depressors, heat thickened fatty oils, sulfurized fatty oils, organo-metallic compounds, metallic or other soaps, sludge dispersers, anti-oxidants, thickeners, viscosity index irnprovers, oiliness agents, resins, nlbber, olefin polymers, voltolized fats, voltolized minerals oils, and/ or voltolized waxes and colloidal solids such as graphite or zinc oxide, etc. Solvents and assisting agents, such as esters, ketones, alcohols, aldehydes, halogenated or nitrated compounds, and the like may also be employed.

Assisting agents which are particularly desirable as plasticizers and defoamers are the higher alcohols having 8 or more carbon atoms and preferably 12 to 20 carbon atoms. The alcohols may be saturated straight and branched chain aliphatic alcohols such as octyl alcohol (CaHi'zOH), lauryl alcohol (CnHzsOH), cetyl alcohol (C16H33OH), stearyl alcohol, sometimes referred to as octadecyl alcohol (CIBHB'TOH), heptadecyl alcohol (CrzHssOH) and the like; the corresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols such as naphthenic alcohols; and aryl substituted allcyl alcohols, for instance phenyl octyl alcohol, or octadecyl benzyl alcohol; or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed naturally occurring alcohols such as those found in wool fat (which is known to contain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol); and although it is preferable to isolate the alcohols from those materials, for some purposes wool fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used, such as alcohols prepared by the oxidation of petroleum hydrocarbons, e. g. paraffin wax, petrolatum, etc.

In addition to being employed in lubricants the additives of the present invention may also be used in motor fuels, hydraulic fluids, torque converter fluids, cutting oils, flushing oils, turbine oils or transformer oils, industrial oils, process oils and generally as detergents in mineral oil products. They may also be used in gear lubricants and greases.

It is also contemplated that the complex esters of the present invention may be employed as lubricating oil base stocks because of their desirable flash point, pour point, viscosity, and viscosity index characteristics. When the complex esters of the present invention are so used, various addition agents may be incorporated therein for the purpose of improving their lubricating properties. For example, anti-oxidants, viscosity index irnprovers, thickeners. pour depressants, dyes, etc. may be added.

What is claimed is:

1. An oil-soluble esterification product obtained by esterfying about 2 moles of saturated dicarboxylic acid having 2 to carbon atoms per molecule with about 1 mole of glycol having 2 to 10 carbon atoms per molecule, and about 2 moles of monohydric alcohol selected from the group consisting of (1) amino alcohols having the formula where R and R1 are alkyl radicals containing 1 to 10 carbon atoms and a is an integer of value 2 to 4', and (2) monohydric alcohols having the formula R'OH where R is an alkyl radical containing 1 to 20 carbon atoms, at least 1 mole of the 2 moles of monohydric alcohol being amino alcohol, and then removing from the resultant esterification mixture by distillation all materials boiling below about 450 C. at atmosphere pressure, said esterification product being the residue remaining after the distillation.

2. A product according to claim 1 wherein said dicarboxylic acid contains 6 to 10 carbon atoms per molecule, said glycol has the formula HO (CI-IzCHzO dCHzCHzOH where d is an integer of value of 0 to 4, the radicals R and R1 contain 2 to 4 carbon atoms, the integer a has a value of 2, and the radical R contains 8 to 13 carbon atoms.

3. A lubricating oil composition comprising a major proportion of a mineral lubricating oil and about 0.001 to 10% by weight, based on the total composition, of a product as defined in claim 1.

4. A lubricating oil composition comprising a major proportion of a mineral lubricating oil and about 1 to 6% by weight, based on the total composition, of a product as defined by claim 2.

5. An oil-soluble esterification product obtained by esterfying about 2 moles of sebacic acid with about 1 mole of ethylene glycol, about 1 mole of a C13 alcohol and about 1 mole of diethylaminoethanol, and then removing from the resultant esterification mixture by distillation all materials boiling below about 450 C. at atmospheric pressure, said esterification product being the residue remaining after the distillation.

6. A lubricating oil composition comprising a major proportion of a mineral lubricating oil and about 1 to 6% by weight based on the total composition of a product prepared by esterifying about 2 moles of sebacic acid with about 1 mole of ethylene glycol, about 1 mole of a C13 alcohol and about 1 mole of diethylaminoethanol, and then removing from the resultant esterification mixture by distillation all materials boiling below about 450 C. at atmospheric pressure, said esterification product being the residue remaining after the distillation.

References Cited in the file of this patent UNITED STATES PATENTS 2,094,608 Kritchevsky Oct. 5, 1937 2,417,281 vVaSson Mar. 11, 1947 2,575,196 Smith Nov. 13, 1951 2,628,974 Sanderson Feb. 17, 1953 

1. AN OIL-SOLUBLE ESTERIFICATION PRODUCT OBTAINED BY ESTERFYING ABOUT 2 MOLES OF SATURATED DICARBOXYLIC ACID HAVING 2 TO 10 CARBON ATOMS PER MOLECULE WITH ABOUT 1 MOLE OF GLYCOL HAVING 2 TO 10 CARBON ATOMS PER MOLECULE, AND ABOUT 2 MOLES OF MONOHYDRIC ALCOHOL SELECTED FROM THE GROUP CONSISTING OF (1) AMINO ALCOHOLS HAVING THE FORMULA 